/**
 * Copyright (C) 2013 The Android Open Source Project Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under the License.
 */
package com.android.volley.toolbox;

import android.content.Context;
import android.graphics.Bitmap;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;

import com.android.volley.VolleyError;
import com.android.volley.toolbox.ImageLoader.ImageContainer;
import com.android.volley.toolbox.ImageLoader.ImageListener;

/**
 * Handles fetching an image from a URL as well as the life-cycle of the associated request.
 */
public class NetworkImageView extends ImageView {

    /** The URL of the network image to load */
    private String mUrl;

    /**
     * Resource ID of the image to be used as a placeholder until the network image is loaded.
     */
    private int mDefaultImageId;

    /**
     * Resource ID of the image to be used if the network response fails.
     */
    private int mErrorImageId;

    /** Local copy of the ImageLoader. */
    private ImageLoader mImageLoader;

    /** Current ImageContainer. (either in-flight or finished) */
    private ImageContainer mImageContainer;
    private BitmapDecorator mBitmapDecorator;

    public NetworkImageView(Context context) {
        this( context, null);
    }

    public NetworkImageView(Context context, AttributeSet attrs) {
        this( context, attrs, 0);
    }

    public NetworkImageView(Context context, AttributeSet attrs, int defStyle) {
        super( context, attrs, defStyle);
    }

    /**
     * Sets URL of the image that should be loaded into this view. Note that calling this will immediately either set the cached
     * image (if available) or the default image specified by {@link NetworkImageView#setDefaultImageResId(int)} on the view. NOTE:
     * If applicable, {@link NetworkImageView#setDefaultImageResId(int)} and {@link NetworkImageView#setErrorImageResId(int)} should
     * be called prior to calling this function.
     * @param url The URL that should be loaded into this ImageView.
     * @param imageLoader ImageLoader that will be used to make the request.
     */
    public void setImageUrl(String url, ImageLoader imageLoader) {
        mUrl = url;
        mImageLoader = imageLoader;
        // The URL has potentially changed. See if we need to load it.
        loadImageIfNecessary( false);
    }

    public void clear(){
        mUrl = null;
        mImageLoader = null;
        if(mImageContainer != null) {
            mImageContainer.cancelRequest();
            mImageContainer = null;
        }
    }
    
    /**
     * Sets the default image resource ID to be used for this view until the attempt to load it completes.
     */
    public void setDefaultImageResId(int defaultImage) {
        mDefaultImageId = defaultImage;
    }

    /**
     * Sets the error image resource ID to be used for this view in the event that the image requested fails to load.
     */
    public void setErrorImageResId(int errorImage) {
        mErrorImageId = errorImage;
    }

    public void setBitmapDecorator(BitmapDecorator decorator) {
        mBitmapDecorator = decorator;
    }

    /**
     * Loads the image for the view if it isn't already loaded.
     * @param isInLayoutPass True if this was invoked from a layout pass, false otherwise.
     */
    void loadImageIfNecessary(final boolean isInLayoutPass) {
        if (mUrl == null) {
            return;
        }
        int width = getWidth();
        int height = getHeight();

        boolean wrapWidth = false, wrapHeight = false;
        if (getLayoutParams() != null) {
            wrapWidth = getLayoutParams().width == LayoutParams.WRAP_CONTENT;
            wrapHeight = getLayoutParams().height == LayoutParams.WRAP_CONTENT;
        }

        // if the view's bounds aren't known yet, and this is not a wrap-content/wrap-content
        // view, hold off on loading the image.
        boolean isFullyWrapContent = wrapWidth && wrapHeight;
        if (width == 0 && height == 0 && !isFullyWrapContent) {
            return;
        }

        // if the URL to be loaded in this view is empty, cancel any old requests and clear the
        // currently loaded image.
        if (TextUtils.isEmpty(mUrl)) {
            if (mImageContainer != null) {
                mImageContainer.cancelRequest();
                mImageContainer = null;
            }
            setDefaultImageOrNull();
            return;
        }

        // if there was an old request in this view, check if it needs to be canceled.
        if (mImageContainer != null && mImageContainer.getRequestUrl() != null) {
            if (mImageContainer.getRequestUrl().equals(mUrl)) {
                // if the request is from the same URL, return.
                return;
            } else {
                // if there is a pre-existing request, cancel it if it's fetching a different URL.
                mImageContainer.cancelRequest();
                setDefaultImageOrNull();
            }
        }

        // Calculate the max image width / height to use while ignoring WRAP_CONTENT dimens.
        int maxWidth = wrapWidth ? 0 : width;
        int maxHeight = wrapHeight ? 0 : height;

        // The pre-existing content of this view didn't match the current URL. Load the new image
        // from the network.
        ImageContainer newContainer = mImageLoader.get(mUrl, new ImageListener() {

            @Override
            public void onErrorResponse(VolleyError error) {
                if (mErrorImageId != 0) {
                    setImageResource(mErrorImageId);
                }
                notifyRequestCompleted(null);
            }

            @Override
            public void onResponse(final ImageContainer response, boolean isImmediate) {
                // If this was an immediate response that was delivered inside of a layout
                // pass do not set the image immediately as it will trigger a requestLayout
                // inside of a layout. Instead, defer setting the image by posting back to
                // the main thread.
                if (isImmediate && isInLayoutPass) {
                    post(new Runnable() {

                        @Override
                        public void run() {
                            onResponse(response, false);
                        }
                    });
                    return;
                }

                if(response != null && response.getBitmap() != null) {
                    setImageBitmap(response.getBitmap());
                } else if (mDefaultImageId != 0) {

                    setImageResource(mDefaultImageId);
                }
                notifyRequestCompleted(response.getBitmap());
            }
        }, maxWidth, maxHeight, mBitmapDecorator);

        // update the ImageContainer to be the new bitmap container.
        mImageContainer = newContainer;
    }

    private void setDefaultImageOrNull() {
        if(mDefaultImageId != 0) {
            setImageResource( mDefaultImageId);
        }
        else {
            setImageBitmap( null);
        }
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout( changed, left, top, right, bottom);
        loadImageIfNecessary( true);
    }

    @Override
    protected void onDetachedFromWindow() {
        if(mImageContainer != null) {
            // If the view was bound to an image request, cancel it and clear
            // out the image from the view.
            mImageContainer.cancelRequest();
            setImageBitmap( null);
            // also clear out the container so we can reload the image if necessary.
            mImageContainer = null;
        }
        super.onDetachedFromWindow();
    }

    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        invalidate();
    }

    public ImageContainer getImageContainer(){
        return mImageContainer;
    }
    
    public void clearCache(){
        if(mImageContainer != null) {
            mImageContainer.clearCache();
        }
    }
    
    /**
     * 通知加载图片完成
     * @param bitmap
     */
    protected void notifyRequestCompleted(Bitmap bitmap) {

    }
}
